<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<CURRENCY> USD

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   9-MOS                   6-MOS                   3-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1999             DEC-31-1999             DEC-31-1999             DEC-31-1998
<PERIOD-START>                             JAN-01-1999             JAN-01-1999             JAN-01-1999             JAN-01-1998
<PERIOD-END>                               SEP-30-1999             JUN-30-1999             MAR-31-1999             DEC-31-1998
<EXCHANGE-RATE>                                      1                       1                       1                       1
<CASH>                                      11,619,294              34,011,617              32,551,645              50,522,744
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                               78,743,695              67,518,397              57,832,747              49,073,840
<ALLOWANCES>                                (3,010,943)             (2,820,675)             (3,306,601)             (2,077,198)
<INVENTORY>                                          0                       0                       0                       0
<CURRENT-ASSETS>                            94,168,136             105,856,827              92,579,695             102,394,461
<PP&E>                                     170,042,601             169,659,060             169,419,155             150,727,612
<DEPRECIATION>                              (8,252,440)             (6,860,974)             (5,768,748)             (2,788,615)
<TOTAL-ASSETS>                             388,838,190             391,104,066             372,108,957             349,646,447
<CURRENT-LIABILITIES>                       22,845,467              25,002,729              28,660,910              28,473,153
<BONDS>                                    216,661,602             215,005,272             196,892,128             178,893,235
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                     71,000                  71,000                  71,000                  73,000
<COMMON>                                       901,153                 901,878                 901,878                 900,729
<OTHER-SE>                                 141,678,607             142,967,691             138,020,798             133,446,512
<TOTAL-LIABILITY-AND-EQUITY>               388,838,190             391,104,066             372,108,957             349,646,447
<SALES>                                    150,927,668             104,297,297              50,717,834             146,918,478
<TOTAL-REVENUES>                           150,927,668             104,297,297              50,717,834             146,918,478
<CGS>                                                0                       0                       0                       0
<TOTAL-COSTS>                               99,597,659              65,513,072              31,569,774              92,030,009
<OTHER-EXPENSES>                            26,404,776              14,978,199               7,346,930              24,181,801
<LOSS-PROVISION>                               368,379                 183,154                 721,804                 887,753
<INTEREST-EXPENSE>                          11,011,854               7,187,814               3,515,544               8,493,224
<INCOME-PRETAX>                             18,175,072              20,179,044               9,748,209              30,625,409
<INCOME-TAX>                                 7,179,153               7,970,972               3,850,543              12,556,418
<INCOME-CONTINUING>                         10,990,544              12,204,722               5,895,841              18,058,941
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                10,990,544              12,204,722               5,895,841              18,058,941
<EPS-BASIC>                                       0.61                    0.68                    0.33                    1.02
<EPS-DILUTED>                                     0.61                    0.68                    0.32                    0.99


</TABLE>